While countless Houstonians are still waiting for rescue, Tropical Storm Harvey has now swallowed another Texas city.

“Our whole city is underwater right now but we are coming!” Port Arthur Mayor Derrick Freeman posted Wednesday morning on Facebook. “If you called, we are coming. Please get to higher ground if you can, but please try (to) stay out of attics.”

At least 24 deaths related to Hurricane Harvey and its aftermath have been reported in Texas. One of them, Houston police Sgt. Steve Perez, drowned while trying to get to work.

In Beaumont, rescuers Tuesday afternoon came upon a toddler in a pink backpack clinging to her mother’s body in floodwaters about a half mile from their car. The girl was in stable condition with hypothermia.

“Had we been a few moments later, they would have been swept underneath (a trestle) and our boats wouldn’t have been able to get them,” Haley Morrow, spokeswoman for the Beaumont Emergency Management Office, told CNN on Wednesday.

“A true testament of a mother who put her own life at risk and sacrificed her life to save her child. That was devastating.”

In Port Arthur — about 90 miles east of the devastated Houston area — the deluge was so severe that floodwaters overwhelmed the Bob Bowers Civic Center, which was serving as a shelter. It was evacuated Wednesday after taking on water overnight, according to volunteer Ana Platero.

Cots where people slept the night before floated on 2 feet of water Wednesday as people waited on tables or sat on elevated bleachers to be evacuated to a nearby middle school.

Police made an appeal for volunteers to bring boats and help.

“Rescue boats welcome in Port Arthur to assist emergency personnel,” the police department posted on Facebook. The city is asking anyone trapped to hang a white towel, sheet or shirt outside to alert rescuers.